Basic Clipping Problem

I'm not sure if anyone else has come across this problem or has a solution. I am working on a project to determine habitat selection of Barn Owls. I have their flight paths and positions layered over the USGS Land Cover (National Vegetation Classification - Formation Land Use) layer that I found from ArcGIS online. I used the buffering tool to buffer the flight paths(lines) and I want to use the Clipping tool to punch out the portions on the vegetation layer that the owls fly over for analysis purposes.

Here's the problem: I used the USGS Land Cover (National Vegetation Classification - Formation Land Use) layer as the input features and the buffered owl flight paths as the clip features. I get a 000840 : The value is not a <value> message and that "the value specified is not a correct input parameter for that particular tool".

The Solution: Set the parameter to a value or field or file of the type specified in the error message.

My quesion(s): How do I go about doing this? Is this possible with the USGS Land Cover (National Vegetation Classification - Formation Land Use) layer? Is it something to do with a raster/vector conversion?

Thank you for your help